Odd drive assignment for HBA

Our SAN group performed some hardware upgrades over the weekend. Now I have a Redhat AS4-64Bit system that is assigning SAN drives in a most unusual way. Prior to this upgrade the Qlogic HBA card assigned the SAN drive to /dev/sda. Now, the kernel reports that /dev/sda is unavailable and assigns the SAN drive to /dev/sdb instead. The drive /dev/sdb does work normally. However, this server is a node for a cluster. The other member is suffering the same problem. I'd rather determine the cause and fix it rather than change all references in the configuration files to the new drive location. Does anyone have any suggestions?